feat: implement batch import recipe functionality (frontend + backend fixes)

Backend fixes:
- Add missing API route for /api/lm/recipes/batch-import/progress (GET)
- Add missing API route for /api/lm/recipes/batch-import/directory (POST)
- Add missing API route for /api/lm/recipes/browse-directory (POST)
- Register WebSocket endpoint for batch import progress
- Fix skip_no_metadata default value (True -> False) to allow no-LoRA imports
- Add items array to BatchImportProgress.to_dict() for detailed results

Frontend implementation:
- Create BatchImportManager.js with complete batch import workflow
- Add directory browser UI for selecting folders
- Add batch import modal with URL list and directory input modes
- Implement real-time progress tracking (WebSocket + HTTP polling)
- Add results summary with success/failed/skipped statistics
- Add expandable details view showing individual item status
- Auto-refresh recipe list after import completion

UI improvements:
- Add spinner animation for importing status
- Simplify results summary UI to match progress stats styling
- Fix current item text alignment
- Fix dark theme styling for directory browser button
- Fix batch import button styling consistency

Translations:
- Add batch import related i18n keys to all locale files
- Run sync_translation_keys.py to sync all translations

Fixes:
- Batch import now allows images without LoRAs (matches single import behavior)
- Progress endpoint now returns complete items array with status details
- Results view correctly displays skipped items with error messages

locales/zh-CN.json

@@ -722,7 +722,7 @@
                 "getInfoFailed": "获取缺失 LoRA 信息失败",
                 "prepareError": "准备下载 LoRA 时出错：{message}"
             },
-"repair": {
+            "repair": {
                 "starting": "正在修复配方元数据...",
                 "success": "配方元数据修复成功",
                 "skipped": "配方已是最新版本，无需修复",
@@ -733,33 +733,55 @@
         "batchImport": {
             "title": "批量导入配方",
             "action": "批量导入",
-            "urlsMode": "URL / 路径",
-            "directoryMode": "目录",
-            "urlsDescription": "输入图片 URL 或本地文件路径（每行一个）。每个将作为配方导入。",
+            "urlList": "[TODO: Translate] URL List",
+            "directory": "[TODO: Translate] Directory",
+            "urlDescription": "[TODO: Translate] Enter image URLs or local file paths (one per line). Each will be imported as a recipe.",
+            "directoryDescription": "输入目录路径以导入该文件夹中的所有图片。",
             "urlsLabel": "图片 URL 或本地路径",
             "urlsPlaceholder": "https://civitai.com/images/...\nhttps://civitai.com/images/...\nC:/path/to/image.png\n...",
-            "directoryDescription": "输入目录路径以导入该文件夹中的所有图片。",
-            "directoryLabel": "目录路径",
+            "urlsHint": "[TODO: Translate] Enter one URL or path per line",
+            "directoryPath": "[TODO: Translate] Directory Path",
             "directoryPlaceholder": "/图片/文件夹/路径",
+            "browse": "[TODO: Translate] Browse",
+            "recursive": "[TODO: Translate] Include subdirectories",
             "tagsOptional": "标签（可选，应用于所有配方）",
-            "addTagPlaceholder": "添加标签",
-            "addTag": "添加",
-            "noTags": "未添加标签",
+            "tagsPlaceholder": "[TODO: Translate] Enter tags separated by commas",
+            "tagsHint": "[TODO: Translate] Tags will be added to all imported recipes",
             "skipNoMetadata": "跳过无元数据的图片",
             "skipNoMetadataHelp": "没有 LoRA 元数据的图片将自动跳过。",
+            "start": "[TODO: Translate] Start Import",
             "startImport": "开始导入",
             "importing": "正在导入配方...",
             "progress": "进度",
+            "total": "[TODO: Translate] Total",
+            "success": "[TODO: Translate] Success",
+            "failed": "[TODO: Translate] Failed",
+            "skipped": "[TODO: Translate] Skipped",
+            "current": "[TODO: Translate] Current",
             "currentItem": "当前",
             "preparing": "准备中...",
+            "cancel": "[TODO: Translate] Cancel",
             "cancelImport": "取消",
             "cancelled": "批量导入已取消",
             "completed": "导入完成",
+            "completedWithErrors": "[TODO: Translate] Completed with errors",
             "completedSuccess": "成功导入 {count} 个配方",
             "successCount": "成功",
             "failedCount": "失败",
             "skippedCount": "跳过",
             "totalProcessed": "总计处理",
+            "viewDetails": "[TODO: Translate] View Details",
+            "newImport": "[TODO: Translate] New Import",
+            "manualPathEntry": "[TODO: Translate] Please enter the directory path manually. File browser is not available in this browser.",
+            "batchImportDirectorySelected": "[TODO: Translate] Directory selected: {name}. You may need to enter the full path manually.",
+            "batchImportManualEntryRequired": "[TODO: Translate] File browser not available. Please enter the directory path manually.",
+            "backToParent": "[TODO: Translate] Back to parent directory",
+            "folders": "[TODO: Translate] Folders",
+            "folderCount": "[TODO: Translate] {count} folders",
+            "imageFiles": "[TODO: Translate] Image Files",
+            "images": "[TODO: Translate] images",
+            "imageCount": "[TODO: Translate] {count} images",
+            "selectFolder": "[TODO: Translate] Select This Folder",
             "errors": {
                 "enterUrls": "请至少输入一个 URL 或路径",
                 "enterDirectory": "请输入目录路径",
@@ -800,7 +822,7 @@
             "emptyFolderName": "请输入文件夹名称",
             "invalidFolderName": "文件夹名称包含无效字符",
             "noDragState": "未找到待处理的拖放操作"
-            },
+        },
         "empty": {
             "noFolders": "未找到文件夹",
             "dragHint": "拖拽项目到此处以创建文件夹"
@@ -1474,7 +1496,14 @@
             "recipeSaveFailed": "保存配方失败：{error}",
             "importFailed": "导入失败：{message}",
             "folderTreeFailed": "加载文件夹树失败",
-            "folderTreeError": "加载文件夹树出错"
+            "folderTreeError": "加载文件夹树出错",
+            "batchImportFailed": "[TODO: Translate] Failed to start batch import: {message}",
+            "batchImportCancelling": "[TODO: Translate] Cancelling batch import...",
+            "batchImportCancelFailed": "[TODO: Translate] Failed to cancel batch import: {message}",
+            "batchImportNoUrls": "[TODO: Translate] Please enter at least one URL or file path",
+            "batchImportNoDirectory": "[TODO: Translate] Please enter a directory path",
+            "batchImportBrowseFailed": "[TODO: Translate] Failed to browse directory: {message}",
+            "batchImportDirectorySelected": "[TODO: Translate] Directory selected: {path}"
         },
         "models": {
             "noModelsSelected": "未选中模型",